Dither signal generation method, circuit and Sigma Delta modulator

The invention discloses a Dither signal generation method, a Dither signal generation circuit and a Sigma Delta modulator. The Dither signal generation circuit is applied to a Sigma Delta modulator, and the Dither signal generation circuit comprises a random number generation unit, a first delay unit, a first adder unit, a first gain unit, a second delay unit and a second adder unit. Seven Dither levels can be generated only through a 1-bit random number, the design requirement of the random number is lowered, hardware expenditure is saved, a transfer function of a control code is ingeniously designed, a Dither signal has a first-order shaping effect, and modulator precision loss caused by Dither D/A conversion errors is greatly reduced. 本发明公开了一种Dither信号产生方法、电路及Sigma Delta调制器。其中，Dither信号产生电路应用于Sigma Delta调制器中，Dither产生电路包括随机数生成单元、第一延时单元、第一加法器单元、第一增益单元、第二延时单元和第二加法器单元；从而仅需1bit随机数就能产生7种Dither电平，降低了随机数的设计要求，从而节省了硬件开销，并且还巧妙设计了控制码的传递函数，使Dither信号自带一阶整形的效果，大大减轻Dither D/A转换误差带来的调制器精度损失。